GLORIA

GEOMAR Library Ocean Research Information Access

X

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Online Resource
    Online Resource
    Gait Abnormalities in Parkinson’s Disease Are Associated with Extracellular Free-Water Characteristics in the Substantia Nigra
    IOS Press ; 2022
    In:  Journal of Parkinson's Disease Vol. 12, No. 5 ( 2022-07-08), p. 1575-1590
    Details
    In: Journal of Parkinson's Disease, IOS Press, Vol. 12, No. 5 ( 2022-07-08), p. 1575-1590
    Abstract: Background: Gait impairments are common in Parkinson’s disease (PD). The pathological mechanisms are complex and not thoroughly elucidated, thus quantitative and objective parameters that closely relate to gait characteristics are critically needed to improve the diagnostic assessments and monitor disease progression. The substantia nigra is a relay structure within basal ganglia brainstem loops that is centrally involved in gait modulation. Objective: We tested the hypothesis that quantitative gait biomechanics are related to the microstructural integrity of the substantia nigra and PD-relevant gait abnormalities are independent from bradykinesia-linked speed reductions. Methods: Thirty-eight PD patients and 33 age-matched control participants walked on a treadmill at fixed speeds. Gait parameters were fed into a principal component analysis to delineate relevant features. We applied the neurite orientation dispersion and density imaging (NODDI) model on diffusion-weighted MR-images to calculate the free-water content as an advanced marker of microstructural integrity of the substantia nigra and tested its associations with gait parameters. Results: Patients showed increased duration of stance phase, load response, pre-swing, and double support time, as well as reduced duration of single support and swing time. Gait rhythmic alterations associated positively with the free-water content in the right substantia nigra in PD, indicating that patients with more severe neurodegeneration extend the duration of stance phase, load response, and pre-swing. Conclusion: The results provide evidence that gait alterations are not merely a byproduct of bradykinesia-related reduced walking speed. The data-supported association between free-water and the rhythmic component highlights the potential of substantia nigra microstructure imaging as a measure of gait-dysfunction and disease-progression.
    Type of Medium: Online Resource
    ISSN: 1877-7171 , 1877-718X
    URL: Article
    DOI: 10.3233/JPD-223225
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2022
    detail.hit.zdb_id: 2599550-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 2
    Online Resource
    Online Resource
    Impairment of Everyday Spatial Navigation Abilities in Mild Cognitive Impairment Is Weakly Associated with Reduced Grey Matter Volume in the Medial Part of the Entorhinal Cortex
    IOS Press ; 2020
    In:  Journal of Alzheimer's Disease Vol. 78, No. 3 ( 2020-11-24), p. 1149-1159
    Details
    In: Journal of Alzheimer's Disease, IOS Press, Vol. 78, No. 3 ( 2020-11-24), p. 1149-1159
    Abstract: Background: Research in rodents identified specific neuron populations encoding information for spatial navigation with particularly high density in the medial part of the entorhinal cortex (ERC), which may be homologous with Brodmann area 34 (BA34) in the human brain. Objective: The aim of this study was to test whether impaired spatial navigation frequently occurring in mild cognitive impairment (MCI) is specifically associated with neurodegeneration in BA34. Methods: The study included baseline data of MCI patients enrolled in the Alzheimer’s Disease Neuroimaging Initiative with high-resolution structural MRI, brain FDG PET, and complete visuospatial ability scores of the Everyday Cognition test (VS-ECog) within 30 days of PET. A standard mask of BA34 predefined in MNI space was mapped to individual native space to determine grey matter volume and metabolic activity in BA34 on MRI and on (partial volume corrected) FDG PET, respectively. The association of the VS-ECog sum score with grey matter volume and metabolic activity in BA34, APOE4 carrier status, age, education, and global cognition (ADAS-cog-13 score) was tested by linear regression. BA28, which constitutes the lateral part of the ERC, was used as control region. Results: The eligibility criteria led to inclusion of 379 MCI subjects. The VS-ECog sum score was negatively correlated with grey matter volume in BA34 (β= –0.229, p = 0.022) and age (β= –0.124, p = 0.036), and was positively correlated with ADAS-cog-13 (β= 0.175, p = 0.003). None of the other predictor variables contributed significantly. Conclusion: Impairment of spatial navigation in MCI is weakly associated with BA34 atrophy.
    Type of Medium: Online Resource
    ISSN: 1387-2877 , 1875-8908
    URL: Article
    DOI: 10.3233/JAD-200520
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2020
    detail.hit.zdb_id: 2070772-1
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
  • 3
    Online Resource
    Online Resource
    Deficient Interhemispheric Connectivity Underlies Movement Irregularities in Parkinson’s Disease
    IOS Press ; 2022
    In:  Journal of Parkinson's Disease Vol. 12, No. 1 ( 2022-01-21), p. 381-395
    Details
    In: Journal of Parkinson's Disease, IOS Press, Vol. 12, No. 1 ( 2022-01-21), p. 381-395
    Abstract: Background: Movement execution is impaired in patients with Parkinson’s disease. Evolving neurodegeneration leads to altered connectivity between distinct regions of the brain and altered activity at interconnected areas. How connectivity alterations influence complex movements like drawing spirals in Parkinson’s disease patients remains largely unexplored. Objective: We investigated whether deteriorations in interregional connectivity relate to impaired execution of drawing. Methods: Twenty-nine patients and 31 age-matched healthy control participants drew spirals with both hands on a digital graphics tablet, and the regularity of drawing execution was evaluated by sample entropy. We recorded resting-state fMRI and task-related EEG, and calculated the time-resolved partial directed coherence to estimate effective connectivity for both imaging modalities to determine the extent and directionality of interregional interactions. Results: Movement performance in Parkinson’s disease patients was characterized by increased sample entropy, corresponding to enhanced irregularities in task execution. Effective connectivity between the motor cortices of both hemispheres, derived from resting-state fMRI, was significantly reduced in Parkinson’s disease patients in comparison to controls. The connectivity strength in the nondominant to dominant hemisphere direction in both modalities was inversely correlated with irregularities during drawing, but not with the clinical state. Conclusion: Our findings suggest that interhemispheric connections are affected both at rest and during drawing movements by Parkinson’s disease. This provides novel evidence that disruptions of interhemispheric information exchange play a pivotal role for impairments of complex movement execution in Parkinson’s disease patients.
    Type of Medium: Online Resource
    ISSN: 1877-7171 , 1877-718X
    URL: Article
    DOI: 10.3233/JPD-212840
    Language: Unknown
    Publisher: IOS Press
    Publication Date: 2022
    detail.hit.zdb_id: 2599550-9
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Online Resource
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...